Speed responsive hydraulic control means



June 27, 1950 c. s. J. MaCNElL ETAL 2,512,803

SPEED RESPONSIVE HYDRAULIC CONTROL MEANS Filed 0ct. 22, 1943 7 2 Sheets-Sheet l 2 4 '-720 768 L un j t R/CHED'E. MOORE FRANK Mac/r June 27, 1950 c. s. J. MacNEu. ETAL 2,512,803

SPEED RESPONSIVE HYDRAULIC CONTROL. MEANS 2.01/3 05 lNvENToRs 730a 730cv CHARLES 5.a MMA/5L 4 "75012 JOHN fr HAM/Es 77 774 /25 HOWARD CARSON /zg plc/mno E. MOORE FRANK MHCK Patented June 27, 1950 SPEED RESPONSIVE HYDRAULIC CONTROL MEANS Charles S. J. MacNeil, John F. Haines, Richard E. Moore, Frank Mack, and Howard Carson, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application October 22, 1943, Serial No. l507,310

Claims.

This invention relates to hydraulic control mechanism for aircraft propellers, and has for an object to reiine centrifugally operated control valves, such that the pitch change effected by them will be consistent -with small increments of initiating power, and also be -corrective in response to small increments of speed change.

Another object of the invention is to simplify the design of a piston and cylinder in a control valve, yet retain features of stability and delity of operation.

A further object of the invention is to provide a control valve with an articulated actuating lever supported by a lever positioning spring or the like, whereby forces transmitted to the valve are restricted to lineally directed forces.

A further object is to provide a control valve with an articulated actuating lever and means for preventing binding of the valve in a casing, whereby the valve will not be inconsistent or erratic in its governing action.

Another object of the invention is to provide a control valve of the class described wherein a valve piston is isolated from an actuating lever except for strictly lineally applied forces.

A further object of the invention is to provide a control valve of the centrifugal type which is opposed by a helical coil spring and a lever 1ocating spring thus rendering it sensitive to small changes in lineally applied forces.

Another object of the invention is to provide a control valve of the clamp on type which may be mounted ywithout distortion of the porting cylinder.

A further object of the invention is to provide a control valve of the centrifugally responsive type whose movement is opposed by a spring actuated lever, and embraces stops marking the high and low speed limits of the valve movement.

A still further object of the invention is to provide means associated with a plunger type valve and porting sleeve for insuring the stability of the valve member within its casing.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. `1 is a longitudinal sectional view illustrating a propeller control mechanism embracing the instant invention, it being a view substantially as indicated by the line and arrows I-I of Fig. 2.

Fig. 2 is a transverse view through the regulator mechanism therefor substantially as indicated by the line and arrows 2-2 of Fig. 1.

Fig. 3 is a plan view of the governor valve assembly substantially as indicated by the arrow 3 of Figs. 1 and 4.

Fig. 4 is an enlarged sectional view thru the governor valve assembly as indicated by the line and arrows 4-4 of Figs. 3 and 5.

Fig. 5 is an elevational view substantially as indicated by the arrow 5 in'Fig. 4.

Fig. 6 is a transverse sectional view thru the governor valve assembly substantially as indicated b-y the line and arrows 6--6 of Fig. 4.

Fig. 7 is a large detail view in section illustrating the relation of the porting sleeve and valve plunger in the neutral position.

Fig. 8 is a similarl view, but with the valve plunger moved to a controlling position calling for an increase of pitch. Y

Fig. 9 is a fragmentary View on a much enlarged scale of one of the valve lands and its associated ports.

With particular reference to the drawings l0 indicates an engine nose or gear casing of an aircraft from which extends a rotatable propeller shaft l2 of hollow construction and to which is secured a propeller hub I4 seated against a rear cone I6 and to be driven by the splines I8. The

hub I4 providesaplurality of sockets 2U withiny which are secured blade roots 22 enclosing torque units 24 for effecting the pitch change of the blades The torque units 24 comprise a cylinder and piston well known to those experienced in the art and in which the piston is moved by the application of a'fluid under pressure to one side or the other of the piston by means of the tubular passages 26 and 28 which are carried to points 36 and 32 of the hub where they align with and communicate with the transfer tubes 34 and 3B embodied in a regulatorplate 36 mounted on a tubular extension 40 of the hub I4. The regulator plate embeds tubular passages 42 and 44 which communicate with all of the tubes 34 and 36 respectively leading to the several blades of the propeller mechanism, andfrom the tubes 42 and 44 extensions 48 and: 5G run to a mounting pad 52 and there open outwardly to the face thereof as at 54 and 56 respectively. A third and intermediate opening 58 communicates with a pressure supply tube 66 also embedded in the regulator plate 38 andwhich leads to a pressure relief valve 62 andthenceby a tube 64 to a pump mechanism 66. i

Mounted over the pad 52 by means of screw devices 61 there is a governor valve assembly 68 3 that distributes iluid under pressure from the opening 58 to one or the other of the openings 54 or 55 and by way of those to either side of the piston in the torque unit 24 and in doing so effects control of Vthe pitchof thepropeller blades. Secured to the" regulator plate-38 isa shell or cover lll which is secured thereto by screw devices 12, and whose inward flange 'Hl of the cover sup-#f draulic iiuid, and with the intake-'off the pump,Y

along with the embedded tubular passages and outlets of the governor mechanism, comprise a self-contained and sealeddhydraulic system. The sealing-ofthe systemis eiiected'by the centrifugally operated seals 82 and' 84 ycarried by the cover and regulator plateresp'ectively, that, under a condition `of'rest are vspring urged inwardly to engage opposite ends of the adaptor' sleeve T8; but whenr'otated` at a'predetermined speed lift away from the adaptorsleeve to reduce friction.

The adaptor sleeve''lafter engaging the bearing 1'5" extends-across the inner bounds of the reservoir where it'enga'ges'a bearing ring i supported by the regulatorl plate 38, and confines the bearing'seal 8'4. The adapter sleeve is retained againstv rotation with the regulator by means-oiscrewdevices 88 passing thru an adaptor plate B, aguide or spacer ringQZ-and threading into a thickened shouldergll vof 'the'adapter sleeve, a-ring gear BB'b'eing'iournalledior rotation about the guide --r`in'g912 and spaced between it and the adapter plate Bil as will presently appear; The adaptorplate 95' has itsiiange notchedat E8 for reception-f a lug |00 extending radially inward from a block |52 secured to the engine nosing, such" that theA adaptor assembly is restrained against-rotationwith respect to the engine nosing by the -singlellug-and'notch engagement 98, H38, but hasla journal bearing'within the bearing rings 'Itj and 85 of the regulator' housing. The thickened portion 94V-of the adapter sleeve provides a toothed flange |04 within the reservoir that meshes with a pinion |06 carried by the pump. 6'6^'and^`thereby effects drivingof thepump, and:

a supply of fluid under pressure, whenever the regulator is rotated.

With particular reference to Figs. Sto Y6 inclusive, the governor valve assembly comprises a block or body |||l that has a mounting face |12 adapted for mounting upon the pad 52 in sealing relation, and Which'is aperturedat llllan'd l I6, and at H8, to line up with the openings 54, S and 58 of the mounting pad 52. Lengthwise of the block there is a bore receivable of a porting sleeve |22 and heldin place by a stop plate |24 and screw device |25. The porting sleeve |22 has peripheral grooves within which are lodgedv synthetic rubber like seal rings |28, which must necessarily be compressed'into the grooves somewhat when the porting sleeve is positioned Within the bore |20, and areso disposed' as to prevent fluid passage lineally of the sleeve from orbetween any one of the'ports H4, H5, l |8. Aside from sealing the porting sleeve and block against leakage, the sealing rings |28 also act as cushion members between the porting sleeve and block when thelatter' is clamped down on the pad 52, since any strains' exerted by the screw devices 61 tending to bind or warp the body |||l are taken up by the packing rings and not transmitted to the porting sleeve as might otherwise be done. The porting sleeve is appropriately fixed with crossv passages to provide setsoi control ports |35,vv |32 mating with the ports ||4 and IIS, and also with pressure ports |321 constantly exposed to the ports 8 of the body lll, the details ofrwhich ports will be treated in .a later paragraph. The porting sleeve 22 has a lineal bore |36 that opens into all of the ports |30, |32and |34 and is traversed by a valve plunger ISS-having spaced lands Ill-0 and |42 for alignment with and coverage of the ports l and'l, as Will be later explained. To one end of the valve plunger there is coupled an actuating lever |44 -by means of a bifurcation |46 straddling a cross pin |48 extending across a slot |5ll in'the plunger, the opposite end of the lever constantly engaging a fulcrum roller |52 mounted on a carriage 45B where it is held'by means of a compression spring |56 engaging a pad |58 and supported from a spring seat |65 threaded-on a stud |52 supported from the plate |24. For purl poses of adjusting spring |56 the stud |62 after passing through the spring seat lllfprovides a iiange its With ratching provisions cooperating Iwith the projecting end of the plate |24 as indicated at |56, andthe stud |762 extends therethru i in a plain bearing to provide a screw driver slot mate portion of the body I0, which prevents the nut fromtur-ningrelative thereto when the stud |52 is turned.

For positioning the lever Mld, so that the bifurcated portion |45 will not push against the cross pin l 48 or otherwise transmita-lateral force to the plunger |38, a lever locating spring |14 connects with the lever Iflbeneath the spring pad |58 where it is secured by a pin llt. The lever ilocatingispring l'llias shown in Fig. 6 is of U-formation and'is formed of thin spring steell with its legs having inward laterally extending arms |'i8v disposable in notches on the underside of the blockl Ill, and apertured to receivescrew devices |86 by which itis secured thereto. The screw devices lslfand-cleat |82 thereby clamping, the ends of. the U-shaped lever locatingv spring il@ between the ends `of the ways and the body H5. The ways i3d are of-chann'el form and set on edge so that their rear or clamped ends seat withinffnotches |86-of the body'l l5 and provide a pair of parallel extending grooves bounded by the respective flanges of the channel members along which the rollers |88 of the carriage |54 are capableeoi rolling. The unattached ends of. the ways l@ have their respective flanges pinched-:inwardly or toward each-other as at torestra-in escape of the. rollers therefrom when the carriage |54 is moved to thel extreme right as viewed in Figs. l and-4.

The carriage is provided with four rollers |88, two on eachside thereof being disposed in the channel of oneof the ways, and it is between the front pair of rollers or those near the free ends of the ways |84 that the ulcrum roller |52 is disposed. Similarly, between the rear pair of rollers, or those nearest thevplunger valve, a second roller |92 is disposed so as Ato be positioned beneath the attached end of the lever |44 to act as a stop whenever the valve plunger is in the underspeedposition or when the regulator is at rest, with the carriage in the full line position-shown in Fig. 4. When' the carriage is in the dotted line position the roller |82 vwill not engage the lever because the fulcrum |52 will be located between the spring |56 and valve plunger |38, so that the plunger and lever will be urged radially outward against the stop plate |24.. For moving the carriage as desired, it is provided with a shoe member 200 which has a pin 202 rotatably carried by the carriage |54, and the shoe 200 is so disposed as to follow a groove of a control ring 204 as illustrated in Fig. 1. The control ring has its groove 206 of non-uniform circular extent about the periphery of the ring such as to provide a slight reciprocatory motion of the carriage as governor valve is rotated about the adapter assembly `without movement of the control ring. For the Want of a more apt term, that reciprocatory motion of the carriage is termed jittering and is incorporated for the purpose of keeping the valve plunger of the governor valve unit in a constant state of agitation While the propeller is in operation, so that the static friction to movement of the plunger will be very much reduced if not eliminated. That is brought about by the fact that though the control ring is in a fixed position along the length of the adapter sleeve, yet the groove being either of ywave form or having its containing plane 'out of the perpendicular to the axis of rotation will have circumferentially spaced points at different distances axially away from the regulator plate 38 supporting the governor valve unit. Hence, as the regulator rotates about the adaptor assembly the Wobbly groove 206 effects a fore and aft movement of the carriage |54 which effects a slight reciprocatory motion of the fulcrum |52. During normal propeller operation the reciprocatory motion of the fulcrum changes the moment arms through which the force of the spring |55 and the centrifugal force act upon the valve plunger and its linkage. Since the valve plunger under the normal propeller operating conditions is in the balanced position with respect to the control ports, then the slight change of moment arms effects a slight domination of the regulating forces exerted on the valve plunger, first the spring force dominates and then 'centrifugal force dominates, with continued and frequent repetition throughout the propeller operation, with the result that there are spurts of uid pressure alternately to one control port and then to the other, as will be presently explained in connection with positive `overlap of the plunger lands.

During a condition of under-speed operation of the propeller, or in those instances when the propeller is running at lovv speed, such as when it is being started or built up to rotation, the valve plunger and lever will then rest against the roller stop |82 as Well as rest on the roller f* fulcrum |52. In this case the jittering movement of the carriage will tend to move the lever along with the valve plunger as a Whole toward and away from the adaptor sleeve 18 without any substantial pivoting over the fulcrum roller or at the cross pin |48, articulating the lever with the valve plunger, and will transmit to the valve plunger a slight reciprocation within the porting sleeve. In either instance the surface tension of the fluid medium between the plunger and sleeve that might tend to bind the parts against free movement is broken. The valve plunger being kept in a state of infinite motion relative to the porting sleeve, it then offers little resistance to further movement by slightly greater forces exerted von the leverage or plunger' by domination of either centrifugal force or .spring force. Hence, the valve plunger is very sensitive to control forces of small magnitude and readily responds to a slight change in speed of propeller operation giving a governed control close to a selected speed level.

The particular speed level is selected by manipulation of the ring gear 96 from the lever 2|2, iby which .the control ring 204 is moved to a desired position along the available length of the adaptor sleeve 18 by means of a plurality of ythreaded control shafts 208 journalled in the adaptor assembly. The shafts 208 each have a pinion 2|0 meshing with the control ring gear 96, the oscillation of which, by linkage attached to they arm 2|2, eifects rotation of the shafts 208 and causes the control ring l204 to move axially of the adaptor sleeve 18, that in turn causesthe carriage |54 to move along the length of the ways |84. For every different position of the fulcrum along the length of the Ways |84 there is a different speed setting at which the regulator will control, since for each positionthere is a different relation of moment arms through which the opposing forces act upon the valve linkage. With the fulcrum roller in the position illustrated in Fig. 4 the setting is for relative high speed, since the spring oifers thegreatest resistance or opposition to outward movement of the valve plunger. If the fulcrum be moved inward to a point between the position shown in Fig. 4 and the axis of the spring |56, then the spring has less opposing force to movement of the valve by centrifugal force, resulting in the equilibrium position of the valve plunger within the porting sleeve being reached at a lower speed of propeller rotation. rIhat fact holds so long as the fulcrum is kept on the right hand side of the spring as shownin Fig. 4. Provision is also made for moving the fulcrum to the other side of the spring or to the other extreme end of the Ways such as shown in dotdash line Fig. 4. In that position the leverage is so changed that the spring force and centrifugal force are now in aiding relation because the fulcrum will be brought to a position between the spring and the mounting face of Vthe governor valve assembly, which causes thevalve .plunger to be thrust radially outward for opening of Athe pitch increase port |32. In fact the spring force alone is suiiicient to hold the valve inthat position, such that there is unrestricted flow from the pressure port' |34 through the control port |32 and the connections with the torque unit to effect an extreme shift to the feathered position of the blades. l

With particular reference to Figs. 7, 8, and 9, of thedrawings, the speciiic relation of the control portsnin the porting sleeve and the lands of the valve plunger are shown. The set of decrease pitch control ports |30, and the' set of'increase pitch control'po'rts |32 are each divided into two pairs of ports or orifices |30a, |30b and |32a, |32b, respectively, the orifices of each pair being diametrically disposed and having the same axial location relative to the sleeve. Of'these pairs, the orices indicated by the subscript a are the pressure applying orifices and are circumferentially spaced 90 from the drain orifices indicated by the subscript b ofthe same set,.while the pressure applying orifices and the drain oriiices of each set are in substantial axial overlapas indicated, yet all are in unrestricted communication with f the respective body apertures |4l l'and 11| 6.

It isaalsmto be notedlthatfthezrpressureapplying .port'slrorioric'es .-,oliiionelsetl areciintaxial alignment withztheifpressure '.applyingf-pcrts-oithe 'otherrset asfalso.;Y obtains for the-sdram :port/slof" each fset, and that :in leach .instance the; pressure applying ports;- .due to the stated `'overlap e with therv drain ports, are each neareirto the'pumpfpressurefrport l3ltthan. are :thescorresponding 'drainxportsr Thefcharacteristcsf ofttheivalve plunger :I 38? are thattheicenter.linesfofeaohlo the lands fl 40T, M2 areficoincidentwith the center lines for set olf.'associateonport's; .but each ilandnhas axial extent, indicated byarroWslrBfthatlslightlyexceed theraxi'alcdimensionioi eacliset of :ports indicated by-f'arrowsf A, .so that therewillbe a .substantial positiveeoverlap otithe .landsfWtli :respectzto the respective set of ports'sa's lrepreseited`by, arrows Ei Thdistancelbetween thefcenterrlinesffornthe set'sfoiicontroli ports` is.' equalfto the distance zbe tweenth'ez'cen'ter lilies for: 'the landssof: the plungenso that whenthevalve is -.in the equi.- libriumA position 2, the. lan-ds kWill overlap all: ports equally.1 Each :land andrset oi #ports bea-rs there# -lationrset out in enlarged detail in .'Fg. 9 for the set of: increase pitchzports,y and where f the land l l l-2:comprises a pair of parallel' peripheral ribs, 220;. 222 :boundingthey :axial limits; .arrows vl5; oi the-land and 'are :sepa-rated Ib'yfa shallowiperipheral groove/224: The axial fli-m-itsoi :the-:ribsfZiZl and. 222- arefsuch 'as to exceed theV axial :dimens sions-.fof :the set ofiportsl 1:32a, lttlb, preerablyfby .001101095 inch, .thus providing :the desiredv overlap; between fthe lands .and ports. Theflocation foi the portsand the dimension of the: lands with their snacings are such that, when the valve 5 initiatinglorce. That'couplediwith theaforesaid jitteri-ngzmotion :oi valveplunger, and the Ap osi- .tive oyerlafpaof -valvelplunger on all :ports results in avery stahleeand balanced pronortionalizingcontrolfvalve.` rEhe amourrtthatfthe valve is J'ittering inthe porting.` sleeve :is notoritical ,hutwshould be greater thanthepositive overlap-ot. the valve ports. In Fig; 9-the boundsnof the :lineal: more ment dueto jitteringis indioatedlbyrthesarrows, Whilei the amount .of jitteriis. represented-by the arrowsfD..y Thei value ot .the jitterV inra four-way valve with positivezoverlap'is to :give :the valve-the proportionalizing characteristics of a negative orerlapifour-vtay valve without introducing the disadvantages r that allowI thev bleeding. of. high pressure .-oil through thegovernor inthe .neutral governing-*position and resulting in forces acting on `thevpistontending to cause unbalance, which would cause-erraticspeed control, instability and Valve chattering. The reason thatathevalve.'pro-y portionalizes is that the jitter allows pressure pulsations to each side of the system for all positions of the piston about Vthe neutral position. Tliesefpr essurezpulsations-control 'the .pressure .in eaclrside of the ksystem with' a minimum `ofpilotv through' .the valve unit. Theflow beingegreatly reduced results in thedorces due :to high velocity 'dow being redu'oedandthe valve-morenearly in hydraulic balance.

lnoperation of. a Vpropeller regulator ttedwith a; governorvalve-:embodying the. stated features;

contrnl's theipitcht offtheblazdes tothe selected speedlevel with great"iidelity,` .andllaccomplshes itlW-ith promptu'ess :softhat there is-.nosuhstantial delay in electing correction to thespeed'level .that might; otherwise-1 occur :due to variations fencountered lin air density, altituderand unevenness ofrair conditions. To `accomplish that'iidelityfoi controlfthe-'yalverfplunger hovers Iaround theneutrai, balanced., or equilibrium-position with respect tozthe porting sleeve.y

Whenfthevalve plunger is: in .the equilibrium positionzas sit liSv-shown 4in :Fig:` 7, .all of. the' controlports -wflll he completely covered :and the ,Waist of theplungerbetween the lands' will: be subject to the: presen/roof` the port l ISIVWhiohlWill. be deliveredfin small spurts to the. control :ports |30, F32;thusskeepingrboth sidesfof the torque-'units full of uid; Butflet theresbesaslight.change'in theespeedtofsrotation of the. propeller, Awhich alters .the fcentrifugal forecasting on ithe'valve yplunger and'lever toy maintaintheY valve plunger in its equilibrium position; thenthefplunger will move along; theportingsleeve l 22 to uncover-one of the control :ports somewhatasshownsin Fig. .8. That movement,.whether it bein response to an ,increase or ay ldecrease of speed, will open the pressure applyingports of one setto pressure from the port; lllll-I and will openl the drain ports, o-f tiranti-1er4 set to drain backto'- the reservoir. Inv Fig; 8,. the valve ports have been. shown moved in response toan increase of :speed withtthe pressure applyingport |3'2a-and thedrain 'port 53th -both open, which vconditions theftorque unit-2t to increase the blade pitch. As the :fluid'under` pressureows to one'side of the torque unit-through the: port I 32a', the other side drains` back to. the reservoir through the drain port-431112. Thelolade'shiit effected changes the load on.- the. motor driving the lpropeller which changes the resultant. speed with auconsequent correction bythe valve. inreturning to the-equilibrium position,

While .the embodimentof the vpresent invention aslhereindisclosed, constitutes' a prei erred form, itis to vloe understoodthatotherfforms might be adopted.,l all coming .withinthe scope .of 'the claims whichiollow Whatfis claimed is as follows.:

LAV .control valvey assembly, comprising in combinatiom. a housing having a bore Atherethrough, avalve plunger slidable-lalona` the bore, a-pair of charmeled` Ways extending.: fromv the housing no1-malto the bore of the cylinder and plunger, a carriage movable along the channels ofthe ywaysfand havingia pair of. rollers, -a lever articulatedwith the valve plunger and adapted to rest onions-of the .carriage rollers as afiulcrum, spring means supported :by the housing and engagingt the lever intermediate the roller'. ful- 50 Crum and valve plunger, andlle'af.springwrneans 9 cured to a mid point of the lever for defining the crotched pivot between the lever and plunger, and a yielding means supported from the valve body for maintaining the lever in engagement with said one roller and for yieldably urging the lever toward the other of said rollers.

3. The combination set forth in claim 2 wherein the hinge spring permits free oscillation of the lever about the fulcrum roller and prevents lateral movement of the plunger due to endwise movement of the lever.

4. In a controllable pitch propeller assembly, a hydraulic regulator, comprising in combination, means providing a reservoir mounted about a central axis, means for rotating the reservoir on the central axis, a governor valve unit mounted in the reservoir, said unit including a porting cylinder and valve piston arranged radially of the axis of reservoir rotation, a spring urged cantilever hinged at one end to the piston and arranged to oscillate in a plane including the axis of reservoir rotation, a carriage providing a fulcrum for the other end of the lever, a roller stop engageable by the lever in the radially 'inward position of said piston, and means for positioning the lever relative to the piston so that oscillation of the lever will transmit only radial forces to the piston, whereby forces tending to bind the piston in the cylinder are eliminated.

5. In a governor valve unit subject to rotation about an axis outside of the unit, the combination comprising, plate means arranged for revolution about said axis, means for rotating the plate means, a valve cylinder Supported on said plate means having its bore radially disposed with respect to the axis of rotation, a valve piston arranged for movement along the bore of the cylinder in response to centrifugal force of rotation, said piston having a pair of lands and an intervening annular groove, said cylinder having a pressure supply port'opening to the intervening groove of the piston, and sets of control ports opening from said cylinder on either side of the pressure supply port7 each of said set of control ports comprising a circumferential row of openings arranged in a staggered relation about the cylinder and providing pressure applying orifices adapted to be connected to the pressure supply port by the intervening groove of the piston, and drain orifices more remote from the said pressure supply port but overlapping with the pressure applying orifices, so that each set of control ports is adapted to be completely covered by one of the lands of said piston, movement of the piston from a position covering both sets of control ports operating to connect the pressure applying orifice of one set with the pressure supply port while opening the drain orifice of the other set to discharge, said lands having a positive overlap on the respective sets of control ports of from .001 to .005 inch, a lever articulated to the piston, a movable fulcrum supporting the opposite end of the lever, spring means urging the lever against the fulcrum to oppose centrifugal force acting on said valve piston due to rotation of the cylinder about said axis, and means effective upon revolution of the cylinder and piston for reciprocating the fulcrum along the lever, whereby jittering of the piston is maintained throughout revolution of the cylinder, said jittering motion of the piston exceeding the total overlap between piston land and associated set of ports.

6. In a governor valve unit subject to movement about an axis of rotation, the combination comprising, plate means arranged for revolution about the axis, means for rotating the plate, 'a valve cylinder supported on said plate means having its bore radially disposed with respect to the axis of rotation, and having pressure delivering ports intervening lineally spaced pressure applying ports, a spool valve arranged for movement along the bore of the cylinderin response to changes in speed of rotation, and having lands lineally spaced to cover the pressure applying ports of the cylinder with a positive overlap, Veach land having a limit of axial extent greater than the pressure delivering ports, a lever and spring coupled to the spool valve for opposing movement of the valve in response to change in speed of rotation, and means for positioning the lever, so that lateral movement of the spool valve relative to the cylinder, due to lateral biasing movement by the lever is eliminated, and means for jittering the spool valve in the cylinder whereby static friction to movement of the valve Within the cylinder is reduced.

7. In a governor valve unit, the combination comprising, plate means arranged for revolution about an axis of rotation, means for rotating the plate means, a valve cylinder' supported on said plate means having its bore radially disposed with respect to the axis of rotation, a valve piston arranged for movementradially inward and outward along the bore of the cylinder in response to change in centrifugal force of rotation, said valve cylinder having a pressure supply port and two control ports, one spaced on either side of the supply port, said valve piston having a pair of lands spaced to'cover both of the control ports but adapted upon movement of the piston along the bore of the cylinder to connect one of the control ports with the pressure supply port and connect the other control port with drain, a lever having an articulatedconnection with the piston and extending at right angles therefrom and parallel with said axis, a carriage having a fulcrum supporting the remote end of the lever, and movable toward and away from the lever and piston articulation, a stop provided by the carriage for limiting the radial inward movement of the piston, spring means resisting movement of the piston along the bore of the cylinder in response to centrifugal force, movement of the carriage al'- tering the ratio of centrifugal force and resisting force applied to the valve, and a hinge spring secured to said cylinder for supporting the lever whereby movement of the carriage and oscillation of the lever will be free from transmitting movement to the piston laterally relative to the cylinder.

8. A governor valve assembly, comprising in combination, a supporting member, means for rotating the member about an axis, a valve cylinder having a pressure supply port and two sets of pressure distributing ports, each set of distributing ports being lineally spaced on opposite sides of the pressure supply port, a spool valve freely movable along the bore of the cylinder and having a pair of lands lineally spaced to cover all of said distributing ports with a positive overlap, means for mounting the cylinder and spool valve on the supporting member so that the bore of the cylinder and spool valve extend along a radius of the rotary axis, spring means for moving the spool valve along the bore of the cylinder in opposition to centrifugal force acting on said spool valve due to rotation of the support, a lever articulated with the spool valve and extending normal thereto, said spring means acting on the lever in a direction parallel to the movement of the spool valve, means preventing the'leveri from i transmittingany; lateral forces tothe 'spoolwvalvev due to endwise movement of `the-lever; including.'x aaleaf spring securedrto' the val-ve cylinder and-' lever, and the lands offsaid spool' valve "havingz wide-annular grooves for reducingrthefmetal. to Y metal Contact ofthe spool valve' withinthecylinder, whereby thestatic friction to movementioi.

the spoolvalve along-the cylinder;-is-substantiallyf' reduced.4

9. A control valve assembly,r comprising in# combination, a support having; pressure and: dis@ tributing.: passages; a' valveh'ousingi. onl the Asupport having a bore `therethrough intersecting said.

pressure and distributing passages, a: porting sleevecarried bythe bore ofthe-housing and; having -sets ofr'distributing ports' and pressure ports, each set'offports opening into-,aseparate passageV oftheV support; saidsleevef having peripheral;

grooves situated-'onv each sidefof .aline ofrpres4 sure ports, and on each sidey of afline -of lineallyl spaced@ distributing ports; meanai exerting a clampngvforce normal -tothe 'boreffor clamping; the' housing to-said support; said' sleeve .having substantial clearance withy the bore-oix` the nousJ ing;: and yieldablepaokingfrings-disposedin the grooves of the sleeve and compressedV betweenthe fsleeve and' housing toseal againstuid 'leakm age between the ports; and'. to-relieve clam-ping strainfon the housing. fromsbeingf-transmitted,to#

the porting-1 sleeve, a :valve `plunger movable` alongv the por-ting sleeve? and havingV landsadapted.:totV

stop -iow through: thedistributing--portabut-'susw ceptibleftomovement for opening a distributing port tothe pressure ports-without binding bef tweenthe sleeveandplunger due to kdistortion off: the housingfpursuant to mounting -on-.thefsup-- port.l

10. Inlaf-controllableI pitch-propeller assembly; a hydraulic-regulator, comprising in combination, means providingA a reservoir., control apparatus mounted-'inefthefreservoirand:including a Ygovernorxvalve unit, meansffor rotating said-reservoir,

said :unitfincludinga; portingy cylinder and piston-1 arrangedzradially offthe axis of rotation; a, spring :j urged: cantilever' hinged to the piston` and, ar-

ranged to osoillatef inpaplane inoludingsthel axis. offrotation; Withi-.theafpiston fmovin'gz' radially inward-andi outwardfaliongI the cylinder;- a 'carriageproviding a-*fulcrum for one end'of theleveng afroller stopfengageabl'e by the :lever in theyre;-

dially inward position of saidvpiston,A centrifugahv foroetendingftomove said piston" andxlever 'outwardsand-away frolfnsaid.V stop, andra springyield-e ablyfresistnge said outward-movement; means for: selectively.,A positioning,`A thefu-lorum along the lengthotlielever; and-:means eiectingfjtter of;`

thef ffulcrum--whilefthef regulator is rotatingre gardlessiof thef'positon of-Lthe tulo-rum alongthe lever, aswell: as duringvunderspeed when the 1 -leverv mayfengage theroller stop.

REFERENCES CITEDi The":followingr references are off 'record' in'. they lef' of this 'pa-tent I UNITED STATES PATENTS 

